Mac OSX server command equivalent for dhclient?

Question

Is there an MacOS command that makes a dhcp request, and renews the old lease, drops it for a new one, or usefully reports errors or lack of response from a dhcp server?

This would both help fix networking on the machine after problems on the network without rebooting and would also be useful to diagnose wider networking problems from a mac.

I can not find any command equivalent of dhclient though obviously some component must be serving this purpose. The question is, is that component exposed to a command line interface?

I am biased to the command line for these features and may have overlooked settings panels or tools that might solve it using a gui interface.

I believe this question is at the heart of this other question: Is there an equivalent command for 'init.d/networking restart' in OS X

Solution

To renew the lease:

sudo ipconfig set <interface> DHCP

Usually interface is en0 or en1.

To see all the gory details, run sudo ipconfig setverbose 1 before you run the above, then tail /var/log/system.log. After you're done, remember to run sudo ipconfig setverbose 0 to turn it off again.

Comments

[John Gardeniers]

Good question but is there any particular reason you're not doing this through the GUI?

[Pavan Kumar]

GUI's are subjected to more changes and the results are harder to capture where as the commands could even be an

[mdiianni]

Usually happens to me when I lock my Mac and log in to my session back again I lost DNS config or resolv.conf doesn't work. So this command saved me the task of disconnecting and reconnecting back to the network to fix it. Thanks.

[Timo]

I did sudo ipconfig setverbose 1and then sudo ipconfig set <my special lan interface> DHCP but no output on console nor new output in system.log.